This disclosure is directed to an apparatus for drilling slant holes. A slant hole is used to tunnel beneath rivers or similar areas. As one example, slant holes can be used to drill under highways and other areas where trenching activities are not acceptable. The slant hole is useful for going under areas where construction work is prevented or costly. In a typical situation, the hole that is drilled is formed at a very shallow angle with respect to the surface. As an example, the well may enter the surface at a slant angle while drilling. Drilling is accomplished by mounting a drive unit connected to a kelly which is rotated by the drive unit. This slant well drilling apparatus is not the same as a conventional well drilling apparatus which forms conventional oil or water wells. The kelly, in turn, is threaded to a first joint of drill pipe. As drilling progresses, additional joints of drill pipe are added between the drill string and the kelly. Moreover, the drilling process utilizes electrically powered and guided control mechanisms at the end of the drill string. The end of the drill string supports a drill bit and various steering devices which enable drilling in the desired direction. The equipment at the drill bit, including the steering device, requires an electrical connection. Ordinarily, this is accomplished by positioning an electrical cable through the drill string extending to the kelly which is a hollow member. Each time a joint is added, the electrical conductor must be cut, additional lengths spliced in it and it must be rethreaded through the added joint of pipe. The present disclosure is directed to an apparatus which reduces the number of cuts required for the conductor string and therefore expedites drilling speed. The present apparatus is incorporated within a drill string to enable quick connection and disconnection, and to further enable continued drilling.
The present disclosure is directed to an insert having the form of a cartridge with protruding lugs. It is axially hollow to provide a flow path through the device for drilling fluid. In the ordinary situation, drilling fluid is introduced through the kelly and is forced through the drill string and emerges from the drill bit. This flow forces electrical cables deployed in the drill string down the drill string to the drill bit. The present apparatus is a device which stores an excessive amount of electrical cable or wire, but it is spooled out slowly to avoid cable accumulation which would otherwise occur. It requires a specified pull on the cable which is held within a housing. The cable is pulled turn by turn from the housing and deployed in the drill string. This avoids bunching of the cable in the drill string.
Through the use of the present equipment, a connector is located in the drill string which enables quick and easy connection and disconnection as a joint of pipe is added. Moreover, the device is readily moved from a first joint of pipe into the new joint of pipe after the first joint has been drilled into the well. This procedurally speeds up the addition of another joint of pipe in the drill string.
The present apparatus is summarized as a cartridge which has protruding tabs or ears which extend outwardly at the top end. This enables it to be locked at a pin and box coupling in the drill string. It has a transverse bar which serves as a hook or eyelet for retrieval so that it can be pulled upwardly. The cartridge has a transverse top end which is drilled in the center with a passage of sufficient diameter to serve as a mud flow path for drilling fluid which is pumped through the drill string. It is relatively short, shorter than a typical joint of drill pipe. Moreover, the top end supports a fixed connector functioning as an electrical feedthrough. The top of the connector connects with an externally directed conductor. The bottom of the connector connects with a coil of wire which is stored in an internal cavity. The wire is sufficiently long to span several joints of drill pipe. It is stored and held out of the way between a pair of cylindrical tubular sleeves. The inner sleeve defines the axial mud flow path while the outer sleeve is concentric around the inner sleeve defining a narrow space. The coiled wire is pulled free through a resilient lip which retards feeding of the wire.